Efficient mineralization of the antibiotic trimethoprim by solar assisted photoelectro-Fenton process driven by a photovoltaic cell

Abstract

In this study, a novel self-sustainable solar assisted photoelectro-Fenton (SPEF) system driven by a solar photovoltaic cell was developed for the efficient mineralization of antibiotic trimethoprim (TMP) in water. A comparative degradation of 200mgL−1 TMP by RuO2/Ti anodic oxidation (AO), anodic oxidation with H2O2 electrogeneration (AO-H2O2), electro-Fenton (EF) and SPEF was investigated. SPEF was proved to exhibit the highest oxidation power, i.e., more than 80% TOC was removed after 360min SPEF treatment of 200mgL−1 of TMP under optimal conditions at pH 3.0, 1.0mM Fe2+ and 18mAcm−2. Influences of current density, pH, initial Fe2+ and initial TMP concentration on SPEF process were also studied. Ten aromatic intermediates generated from hydroxylation, carbonylation and demethylation reactions were identified using UPLC-QTOF-MS/MS system during the SPEF treatment, together with three carboxylic acids (oxamic, oxalic and formic acids) and two inorganic ions (NH4+ and NO3−) measured. Therefore, a reasonable pathway of TMP degradation in SPEF process was proposed.